I already own the iworks software for my computer. how do I transfer it to iPad so I won't have to pay again?

You don't, it's a seperate suite of software. The iPad has the specific iWork version made only for iPad along with special pricing of $9.99 each for Numbers, Pages and Keynote.

However any documents edited or created in both MAC and iPad if both versions are to the latest updated versions, will share or use the documents made in each.

Thanks very much for your quick reply. I thought it was too good to be true.